There are many data recovery programs for cards. See if any from http://www.google.com/search?q=sd+card+data+recovery is able to recover those pictures. I can't recommend any from personal experience.
Hi! I have an old [but great] Olympus digital camera. It has an 8 MG Smart Media card. I took about one hundred sixty pictures of my students at camp this week. I checked from time-to-time to ensure that my pictures were good. On the last day of the camping trip I noticed that my camera screen showed a giant exclamation point. I could not take anymore pictures. I could not view any of the previous pictures. When I got home from the trip I inserted the memory card into my computer reader. It wanted to format the card. I went to Rite-Aid to use their reader. It was not recognized the memory card. What can I do? I have thirty students whose week of memories may have disappeared. Again, please help!